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As some of you may know, I just recently got my car back on the road after it burned it's fuel relay causing the car to stall out. Needless to say I was excited to have my baby back. However just today, another problem arose. While on my way back from errands I was merging on the highway and gave it a decent punch (as you do). Nothing too aggressive, only brought it up to about 4500 rpm maximum. Immediately after this I began to smell burning oil so I pulled to the side of the road and popped the hood. I was greeted by a layer of oil covering almost the entire drivers side of the engine. It had gotten on to the exhaust manifold, hence the burning smell. There was no active leak, however I could see a telltale splatter mark on the hood heat shielding on the spot that sits above the oil filler neck/cap. I ran across a thread where somebody had a similar issue to me and it turned out to be a loose filler neck, he could actually move it slightly in all directions. However this is not the case for me, my valve covers are on tightly and there is nothing visually wrong with my filler cap. According to the car, I lost a quart of oil in about 15 seconds (just did an oil change 200 miles ago so I know it was full). I sat idling the car to burn the oil off of the exhaust manifold in a controlled way, cleaned all of the visual oil off of the filler neck and valve cover and then made my way home, never bringing the car above 2500 rpm. I checked when I got home and it seems to me that no more oil had leaked out after the initial incident. Car is not throwing a code. Is there an easy way to check a bad oil filler cap? The only other thing I can think of would be a problem with crankcase ventilation, although I think I remember reading somewhere that these cars don't have PCV valves. As a note, there is no detectable vacuum at the filler neck when the car is idling, not sure if that means anything on these cars but I know it does on other platforms.
When you did the oil change, did you use a mann filter and change the o-rings? There is pressure in the filter cap, and if your top o-ring is above it's groove, oil will spray. The middle o-ring is ------------ skratch that, they are all important.
Simple question...is the oil filter cap tight? Just had a similar situation with my son's m112 in his w202.
Almost positive it was, I was sure to check that exact thing when I got to the side of the road and it was on as tight as possible.
Originally Posted by StarvingArtist
When you did the oil change, did you use a mann filter and change the o-rings? There is pressure in the filter cap, and if your top o-ring is above it's groove, oil will spray. The middle o-ring is ------------ skratch that, they are all important.
Originally Posted by Yuille36
All that oil is a headache to fully remove, but from the looks of the photo, it could have come from the oil filter cap.
Yes, a Mann filter from FCP Euro was used and all four O-rings were changed. I'll take off the filter cap and check the o-ring positions today. Thanks guys
There is pressure in the filter cap, and if your top o-ring is above it's groove, oil will spray. .
M112 example.
Precisely, The filler cap fails at the seam, oil does not "spray" from the filler cap, more like leaks or "weeps" . Unless it comes apart and the cap portion is completely separated. It's hard to see it for sure but your filter cap does not look completely seated?
You can see the seam fails and the cap splits into 2, it's got some orange RTV spewing out where a temporary repair was made. Here is what the replacement looks like.
Precisely, The filler cap fails at the seam, oil does not "spray" from the filler cap, more like leaks or "weeps" . Unless it comes apart and the cap portion is completely separated.
You can see the seam fails and the cap splits into 2, it's got some orange RTV spewing out.
Yeah mine was most definitely a spray, not a slow leak. My filler neck looks to be intact, or at least doesn't exhibit any of the symptoms in the pictures you shared. I removed the filter housing and all of the O-rings are properly seated. However I did notice that the cap (the part that is exposed when the filter is in place) was able to move slightly, independently of the long straight part that the other three O-rings are mounted on. Wondering if this is normal? I can't remember if it was in my past oil changes.
I removed the filter housing and all of the O-rings are properly seated. However I did notice that the cap (the part that is exposed when the filter is in place) was able to move slightly, independently of the long straight part that the other three O-rings are mounted on. Wondering if this is normal? I can't remember if it was in my past oil changes.
Did you remove the filter cap by hand? Yes the stem moves around a bit.
As some of you may know, I just recently got my car back on the road after it burned it's fuel relay causing the car to stall out. Needless to say I was excited to have my baby back. However just today, another problem arose. While on my way back from errands I was merging on the highway and gave it a decent punch (as you do). Nothing too aggressive, only brought it up to about 4500 rpm maximum. Immediately after this I began to smell burning oil so I pulled to the side of the road and popped the hood. I was greeted by a layer of oil covering almost the entire drivers side of the engine. It had gotten on to the exhaust manifold, hence the burning smell. There was no active leak, however I could see a telltale splatter mark on the hood heat shielding on the spot that sits above the oil filler neck/cap. I ran across a thread where somebody had a similar issue to me and it turned out to be a loose filler neck, he could actually move it slightly in all directions. However this is not the case for me, my valve covers are on tightly and there is nothing visually wrong with my filler cap. According to the car, I lost a quart of oil in about 15 seconds (just did an oil change 200 miles ago so I know it was full). I sat idling the car to burn the oil off of the exhaust manifold in a controlled way, cleaned all of the visual oil off of the filler neck and valve cover and then made my way home, never bringing the car above 2500 rpm. I checked when I got home and it seems to me that no more oil had leaked out after the initial incident. Car is not throwing a code. Is there an easy way to check a bad oil filler cap? The only other thing I can think of would be a problem with crankcase ventilation, although I think I remember reading somewhere that these cars don't have PCV valves. As a note, there is no detectable vacuum at the filler neck when the car is idling, not sure if that means anything on these cars but I know it does on other platforms.
I had this happen on my c350 and I had to buy a oil cap.
Update: Did it again today under moderate throttle. I'm almost positive it's the filler cap now based off of the pattern of the oil, there is almost none on the filter cap and a ton all over the filler cap. Going to park the car for the mean time until the new cap gets here and will update on what happens after the install.
Dumb question, but I gotta ask it... You did remove the old oil when you changed it right? Both plugs. There shouldn't be any volume of oil in the filler cap, and only crankcase pressure which should be very low.
Dumb question, but I gotta ask it... You did remove the old oil when you changed it right? Both plugs. There shouldn't be any volume of oil in the filler cap, and only crankcase pressure which should be very low.
Yes, I emptied oil through both of the drain bolts. It's possible my crankcase pressure is messed up, but I don't know how to check that.
Update: Did it again today under moderate throttle. I'm almost positive it's the filler cap now based off of the pattern of the oil, there is almost none on the filter cap and a ton all over the filler cap. Going to park the car for the mean time until the new cap gets here and will update on what happens after the install.
I'd wrap them both with aluminum foil and repeat the test.
It was the oil/ intercooler hose right in front of the oil filler. I think mine failed due to too much flex from bad motor mounts before I got the car. Because it sprayed about five quarts of oil, I would not have found the issue without cleaning and running it while reving it. There a kits to fix this as new hoses are very expensive, which I had to get from Germany.
If it is the oil-to-oil cooler hose/fittings, replace them with a set from DavesMeanE's here on the board. I purchased a set of fittings from him earlier this year; quality work.
Definitely check the cooler lines right in front of the filter housing. Take a real good look at the hoses close to the metal crimp and carefully move the hoses back and forth to reveal any splits or pin holes. I chased this same problem for weeks! Good luck!
Big thanks to everyone helping out, this is why I love this community. I wrapped the oil filler neck and filter cap in aluminum foil and recreated the leak. To my surprise, it was neither of those. They were both squeaky clean. Sucks that I already ordered a new filler cap but it was only $5. This is why you don’t replace parts randomly I guess haha. Leading theory now, as many of you have pointed out, are oil cooler lines. I spent the better part of this evening removing my fan shroud and poking around, but ran out of light before I could look at the cooler lines more. Going to take another crack at it, might try wrapping the individual lines next and seeing if I can isolate it that way. I fear that I’ll be chasing this problem for at least the next few days though. Will update again in a few days. Once again, thanks for all of your help thus far!
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Oil Geyser from Filler Cap
